Pick a fish, any fish. Everyone has a favorite, just maybe not the one you might think.

Rainbow trout? A beauty for certain. Smallmouth bass? Arguably the most under-appreciated sport fish in the land. Largemouths? Surely America’s fish, but it just doesn’t translate.

“Worldwide, there’s more carp tackle sold than bass and trout tackle combined,” said Kirk Deeter, author of ” The Orvis Guide to Fly Fishing for Carp.” “It’s the most popular fish in the world, the soccer of fishing.”

Much like soccer, carp fishing has been slow to catch on in the U.S. But its popularity is growing. And here in Colorado, carp’s stock is rapidly rising among fly fishermen. Although not even close to the top species of fish targeted in the state – that would be trout – carp are the fish that individual anglers spend the highest average number of days fishing for statewide (49 days a year), according to the most recent anglers’ survey published by Colorado Parks and Wildlife.

That’s likely a nod to both the challenge and the proximity of carp.

For better or worse, carp seem to have become Denver’s signature fish, serving as the focal point of Denver Trout Unlimited’s annual Pro-Am Carp Slam fundraiser for enhancing the urban South Platte River. Dozens of carp chasers line up for September’s already sold-out tournament in an effort to raise enough cash and awareness to turn the local waterway into a bona fide trout stream.

But while the fundraiser is a success, the anglers often fail to catch a fish.

“You do have to be somewhat of a glutton for punishment, no doubt,” said Deeter, who has yet to land a fish in two years of Carp Slam competition. “On one hand, it takes a real experienced angler willing to go through that learning curve. But on the other hand, it’s super accessible. You have fish all around you, so you have opportunities. It’s all about opportunity.”

So what’s the allure of hooking up with what so many people consider a “trash fish?” The appeal is two-fold. Obviously, the tug of a 10-to-20-pound carp on a flimsy fly rod isn’t something the average trout fisherman experiences every day. But more compelling for many is the puzzle of how to find and catch a carp.

“When you’re trout fishing, you can kind of pattern the fish: what they eat, where they like to hang out. You’re really just synching up with the pattern,” Deeter said. “Carp are almost impossible to pattern. They’re all eating differently and it can change abruptly. For that reason, I think carp fishing elevates your game. You’re constantly doing that problem solving, thinking quicker, more on your feet. You have to improvise more.”

Carp tend to use all their senses as well or better than any fish. They have a keen sense of smell, excellent vision, a sense of vibration that extends to their hearing, and some even believe a carp can remember what a hook tastes like. Although they may be omnivores, they are notoriously finicky eaters.

The best way to catch carp with a fly rod? Crayfish and clouser minnows are good first-choice fly patterns, but must be accompanied by long, accurate casts and well-timed hook sets.